Tamper evident seal may be used to increase consumer safety by showing whether a package has been opened after being produced. Tamper evident indicators may include a pop-up button in the center of a package and a break-away seal connected to the lower edge of a lid. The pop-up button has the disadvantage that it may be difficult to ascertain whether the seal has been broken. The break-away lower lid section may be too sensitive and may break away inadvertently during normal jostling. Alternatively, the break-away lower lid section may be insensitive to tampering or pilfering, and may not break away until after the seal between the closure and the container has been breached. The latter situation raises the possibility that the container may be accessed and resealed without breaking the tamper evident seal. This possibility undermines the purpose behind the tamper evident seal, thereby reducing consumer confidence in a product sealed in this manner.
The following patents are believed discuss tamper evident seals. U.S. Pat. No. 3,306,482 is believed to describes a safety closure for containers including first and second relatively rotatable and axially movable members, and engageable and disengageable clutch means which are operable respectively to disable and enable relative rotation of the members.
U.S. Pat. No. 3,438,528 is believed to describe a cap having a tamper indicating skirt joined to the lower end of the cap sidewall by frangible bridges of plastic and a sealing disc which seals against the rim of the bottle neck.
U.S. Pat. No. 4,807,770 is believed to describe a tamper evident, vacuum indicating closure for a container for the packaging of a vacuum-packed product. The closure is of two-piece construction and has a metal lid portion which is retained in sealing engagement with the rim of a container by a plastic ring portion.
U.S. Pat. No. 5,031,787 is believed to describe a closure having an axially movable insert disk which is lifted by a bead around the inside of the closure shell to open a sealed container.
U.S. Pat. No. 5,884,788 is believed to describe a tamper-indicating closure for a container which includes a cap with removable panels of a top wall of the cap. Each removable panel is connected to a tab on the inside of the cap. The top wall includes inner and outer cams on an inside surface and the tabs underlie the cams.
U.S. Pat. No. 5,984,124 is believed to describe a pilfer-proof cap made of synthetic resins capable of preventing at least a rotation of a packing together with a cap in a simple construction when the cap is removed. The cap holds a sealed-up tightness of a container until a bridge is broken is provided.
U.S. Pat. No. 6,382,444 is believed to describe a tamper evident closure for containers having a finish with thread means and a radially outwardly circumferentially extending bead below the threads. The closure includes a cap portion, a retainer ring, and a tamper evident band. The cap portion is of cup-like form and has internal threads for cooperatively engaging the threads on a container to apply and remove the cap portion. The retainer ring depends from the lower edge of the skirt portion of the cap and is connected thereto by a series of circumferentially spaced bridge connections. The tamper evident band has means for rotatably mounting on the retaining ring, is rotatable thereto, and includes a series of spring fingers for engaging under the retainer bead on the container when the closure is fully seated.
U.S. Patent Application Publication No. 2002/0144971 is believed to describe a closure for a container consisting of a top wall and a sealing disc with flexible annular ring.
However, none of the foregoing patents or publications is believed to describe a two-piece, tamper-evident closure that includes a delay-release mechanism, which may maintain a sealing disk on a container until the tamper-evident device shows evidence of tampering.